This invention relates to wood-concrete composite systems, which include at least one wooden component, and a concrete component.
Patent DE 44 06 433 C2, the content of which is incorporated herein by reference, discloses wood with inserted bonded shaped parts to connect with materials of any kind. The known connection system includes flat body in form of a steel sheet, which is bonded partially into a wooden component and partially extends beyond the wooden specimen. The exposed section of the connection system serves to connect to further materials.
From the disclosure of DE 198 08 208 A1, the content of which is incorporated herein by reference, it is known to connect wood to concrete by glued-in shaped parts. This known wood concrete composite connection includes flat bodies in form of steel sheets, which are bonded with one end into a slot in the wood and which reach over the wooden surface with the other end. The exposed end of the steel sheet includes anchor tongues, which are then encapsulated by the poured concrete.
From the disclosure of DE 198 18 525 A1,the content of which is incorporated herein by reference, it is known to connect multiple joined boards with an upper concrete layer through steel bars. The composite action between the wood and concrete is created through a shear connector which extends half way into the wooden and concrete section through a mechanical interlock. The shear connectors are oriented perpendicular to the grain of the wooden specimen in order to generate suitable load bearing forces.
In U.S. Pat. No. 5,561,957 to Gauthier, an intermediate layer 10 and 11 is physically located between the wood 1 and the concrete 2. However, this layer 10 and 11 does not separate the wood from the concrete. In other words, Gauthier therefore relies on the fact that the concrete 2 rests directly on the wood 1, thereby suffering from the drawbacks of the prior art.
In PCT application No. WO94/11589 to Bettex, although having what might be considered an intermediate layer 4 and the shear connection 2 between the wood and the concrete, here too, the intermediate layer 4 does not separate the wood and the concrete in the area of the shear connection 2.
A substantial disadvantage of the aforementioned prior art is the unsatisfactory composite action between the materials wood and concrete and the limitations resulting from the direct connection of these materials. It is known that a direct contact between wood and concrete can lead to condensated moisture and thus to fungus growth in the wood.
It is also known that a direct contact between wood and concrete creates a sound coupling, which prevents the serviceability of a wood-concrete composite floor unless further sound insulation elements are added.
A further disadvantage of the aforementioned prior art is the fact that any inserts such as cables and/or pipes into the wood and/or concrete section undergoes stresses which reduce their long term performance.
What is needed is a method of creating a wood concrete composite system which provides for uncoupling of the totally different materials wood and concrete, without reducing the rigid and/or stiff connection—a sole condition for an effective composite action—of the two materials.